1. Field of the Invention
The present invention relates to a substrate processing apparatus for executing processing on a substrate and to a method for handling a substrate while restraining the substrate from being electrically charged. Examples of the substrate to be processed or handled include a semiconductor wafer, a liquid crystal display substrate, a plasma-display substrate, an FED (Field Emission Display) substrate, an optical-disk substrate, a magnetic-disk substrate, a magneto-optical-disk substrate, a photomask substrate and the like.
2. Description of Related Art
In a semiconductor device manufacturing process, a single-substrate-processing-type cleaning apparatus is used for cleaning the surface of a semiconductor substrate (wafer) Such a substrate cleaning apparatus has: a carrier holding unit for holding a carrier which houses a plurality of substrates; an indexer robot for carrying a substrate in and out from the carrier held by the carrier holding unit; a substrate processing unit for processing a substrate using a treatment liquid or the like; and a main transfer robot for transferring a substrate between the indexer robot and the substrate processing unit.
The substrate processing unit has, for example, a spin chuck for rotating a substrate as held substantially horizontal, and a treatment liquid nozzle for supplying a treatment liquid (a chemical or a rinse agent) to the surface of a substrate held by the spin chuck, these spin chuck and the nozzle housed in a processing chamber.
In the component elements housed in the processing chamber, a resin material such as PTFE (polytetrafluoroethylene resin), or PCTFE (polychlorotrifluoroethylene resin) is frequently used in view of resistance to chemical. The members made of such resin material are readily electrically charged. Accordingly, when a substrate is carried in the space in the processing chamber, the substrate is electrically induced and charged, causing the substrate to present a high potential. Therefore, when a treatment liquid is supplied to the surface of a substrate held by the spin chuck, electrical discharge is induced immediately before the treatment liquid reaches thereto. This disadvantageously breaks down the film formed on the substrate surface or devices formed in the substrate. Further, when a processed substrate is carried out from the processing chamber, the substrate is electrically induced and charged again. Thereafter, when the substrate comes in contact with a member which is electrically grounded, this induces electrical discharge.